Still can't get the metal earth strip in. There's just too many wires to squeeze in. What's the consequences of not doing it I'm worried!
Take the fixed wiring, that you have inserted into the block, out again - so that the light fitting looks like it did when you bought it (in your 3rd picture, I think).
Now you have only the 'line' and 'neutral' connections of the light connected to the block.
Turn the block around and slide the middle terminal over the 'earth strip and tighten up. (same side as the 'Line' and 'neutral' are connected to.)
Now make the connections required with the other wiring, to the other (empty), side of the block.